Certain 7-carboxy substituted steroids, for example eplerenone, are well known for their aldosterone antagonist activity and are thus useful in the treatment and prevention of diseases of the circulatory system. U.S. Pat. Nos. 4,559,332 and 5,981,744 and International Publication WO98/25948 describe a number of methods for the preparation of eplerenone and related compounds. However, the advent of new and expanded clinical uses for eplerenone create a need for improved processes for the manufacture of this and other related steroids. A major obstacle to the efficient synthesis of eplerenone and related steroid compounds is the introduction of a carboxy group at C-7. The current syntheses. involve the use of toxic cyanide reagents for the introduction of a C-7 carboxyl group.